Magical Immunity: not too good IMO.
1) You can give it to the titans, just cast Anti-Magic
2) You can't be blessed or resurrected

Flyers + High speed: it doesn't matter if you have ranged attack. Even if you fly over the battlefield, you will still get hit by retaliation. The only bonus is you can deal full damage, but I suppose you could just cast Precision or Bless on the Titans for that.

JUst two things to say:

1- Try making a WoG: Lord of Thunder vs. Darkness Dragon war!! They have different perks and stuff so it could be a very diferent war.
1- Getting Orb of Vulnerability isn't too likely.
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the dragon has a disadvantage decause of hit and run, he has to waste a turn to stop near the titan. in the other hand he is immune to magic, so the thunderstrike shouldn't harm him.
I feel the lord of thunder would win.

Me, too.
Blackys are killin' machines, but that's just about everything they are.U just send them whereever and they start killing like sociopaths.A destructive force, they have no rivals in 2 vs 1, respectevely 3 for Thunderbirds (considering growth rate in H4), but can be defeated by the use of spells.The same goes for H3 and 2.When u say spells u usually say Heroes and that's what this game is about.
This replay also shows they can be defeated, even without spells, wich means Titans have my vote.I just love it, added it to Favourites, thx a lot.

I've found the most terrifying opponent to go up against is a black dragon. There's no curse you can hit it with to slow it down from a hero standpoint. Even some of the stack creatures like genies, have trouble with black dragons.

Remember that even though Titans have mind immunity, they can still be jinxed with a lot of curses.

That fire breath can be a deadly thing. I've seen two stacks get wiped out with one well placed attack, thus changing the whole situation in one turn.

The equilizer is that black dragons generate so slow, and are very expensive.

Still if I could pick 20 of any creature to take in my army, it would be the black dragons. If I only had 8000 gold I would rather it be 2 titans than 1 dragon.
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Titans. They can be adapted the best to the situations given. Black dragons have 1 role and 1 role only; titans can have 100 roles. See, i prefer a lot of options in battle and a well working group of units that can be adapted to any situation.

It's true titans can be boosted like hell with spells. On the other hand they can be taken down by spells as well. In H4 they aren't immune to mind control (or anything at all) which makes them really vulnerable IMO. If you have dragons, you'll have dragons until the very last.
Thats why black dragon is the best for me.

Indeed, if we put a titan against a black dragon in a 1v1 combat, obviously the dragon won. But let's put this issue in a real game. Normally, when you buy your Titans or DBs, you already have a noticable number of spells. This favours the Titan's side. Also, the Titan is cheaper, so normally when it comes to battle, Titans can have about 10% more in quantity, as it might have been bought sooner than the BD.

However, under equal circumstances the BD goes first. Keeping the 'hates Titans' ability in mind (HoMM3) , it will do more damage, and the titan retaliates only after being hit (still HoMM3, not 4). True, it also inflicts more damage, but only fewer number of creatures can do so as the BD has already attacked. Mathematically, this favours the BD, as +50% of more damage points is > +50% of less damage points.

So in a real game situation things can differ. To tell the truth, I don't really know which one is better. It depends on too many things.
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I don't mean to be stroppy or anything, but according to scientific viewpoints, alcohol is indeed a solution.

Black dragons are the best fly up close and overkill enemy unit in the game. No arguments there. However, as battles go, I prefer just a bit more strategy than that entails. Hence, I find titans more fun to use. In terms of power, they seem equal. The two differences is that titans have range, therefore you are less likely to accidentally lose one or two fighting a slightly weaker enemy. Conversely,black dragons have the potential to devastate factions that depend on certain spells.

For me in H4, titans. But there's definitely a case to be had for both sides
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Much more trustworthy than the man in black.

In my opinion
1)in HOMM2 TITANS ARE BETTER THAN DRAGONS(AND THE BETTER UNIT IN THE GAME)
2)IN HOMM3 DRAGONS ARE BETTER
3)IN HOMM4 DAGONS ARE BETTER TOO
4)IN HOMM5 IS A VERY DIFFICULT CHOICE(BUT I PREFER TITANS)

huh what?
the titan is the most expensive unit in both H2 and H3 and in H4, they are as expensive as most other levels 4.
in another hand, the giant is very cheap in homm 3, kinda like the behemoth if I remember well, so you can have them before your opponents has red dragons, but most likely he will have black dragons before you can get titans.